Using LDA+U, we investigate Li-doped rutile SnO2(001) surface. The surface defect formation energy shows that it is easier for Li to be doped at surface Sn site than bulk Sn site in SnO2. Li at surface and sub-surface Sn sites has a magnetic ground state, and the induced magnetic moments are not localized at Li site, but spread over Sn and O sites. The surface electronic structures show that Li at surface Sn site shows 100 spin-polarization (half metallic), whereas Li at sub-surface Sn site does not have half metallic state due to Li-Sn hybridized orbitals. The spin-polarized surface has a ferromagnetic ground state, therefore, ferromagnetism is expected in Li-doped SnO2(001) surface.
Cite
@article{arxiv.1402.3262,
title = {Spin-polarized surface state in Li-doped SnO$_{2}$(001)},
author = {Naseem Ud Din and Gul Rahman},
journal= {arXiv preprint arXiv:1402.3262},
year = {2014}
}